Crossfire Designs MidiPads, £2.99

Compatibility: iPad (requires iOS 4.2 or later)

Turn your iPad into a drum pad controller via network or USB MIDI. There are four pages, each of which contains 16 touch-sensitive and resizable pads, while sliders and an XY pad are also included. There’s “easy MIDI learn”, apparently, which will hopefully make assigning the controls a breeze.

Mode of expression Noteplex, £1.19

Compatibility: iPad (requires iOS 4.2 or later)

Noteplex promises to present the user with “a new and unique way to experience music”. It offers a hexagonal board of cells onto which you can place nodes, each of which has a specific sound associated with it (your own samples can be used too). Nodes then fire pulses that trigger other nodes, which then fire pulses of their own. Thus, a song is gradually built up.